The total amount of data on skeletal muscle metabolism published during the last 15 years contrasts with the paucity of information on smooth muscle metabolism over this same period. Recently, we have been studying the intermediary metabolism of nonhuman primate myometrium during pregnancy and the follicular and luteal phases of the menstrual cycle. The overall goal of our studies on this smooth muscle is to gain information on metabolic control mechanisms; interrelationships of carbohydrate, lipid, and protein metabolism; and cyclic nucleotide metabolism. We have collected and stored (-200 degrees C) myometrial samples from 24 cycling monkeys and 12 myometrial samples from spayed animals after the administration of estradiol or estradiol plus progesterone. The total activity and kinetics of the rate-limiting enzymes for glycolysis will be studied in these myometrial samples and the activity of the enzymes synthesizing and degrading adenyl and guanyl cyclase. Plasma estradiol and progesterone levels in these animals will be correlated with changes in metabolism. BIBLIOGRAPHIC REFERENCES: Beatty, C.H., Bocek, R.M., Young, M.K. and Novy, M.J. Effect of indomethacin on cyclic AMP phosphodiesterase activity of myometrium from pregnant rhesus monkeys. Prostaglandins 11:713-725, 1976. Bocek, R.M. and Beatty, C.H. Cyclic AMP phosphodiesterase activity in fetal and adult muscle of the rhesus monkey. Dev. Biol. 48:382-391, 1976.